1. Field of the Invention
This invention relates generally to a class of equipment known as wireless terminals such as mobile telephones and pagers; and, more specifically, to selectively controlling the powering-down and duration of the power-down time of a wireless terminal.
2. Description of the Prior Art
Wireless terminals such as pagers and mobile telephones are being used more extensively by more people for more varied purposes each year. A pager is generally used by a calling party to alert a called party that someone is trying to contact him. This is usually done by the caller calling a Personal Telephone Number (PTN) assigned to a pager subscriber by a pager service provider. The pager, normally a small device carried in a pocket or on the belt of a subscriber, displays the telephone number of the caller and emits an audible sound such as a beep, or vibrates, to alert the subscriber that a call has been sent to his pager. Once alerted, the subscriber, upon seeing the number, goes to a telephone to call the number displayed. As technology has grown, pagers have evolved from providing only telephone numbers to providing more complex alphanumeric messages. They are even capable of accessing other services such as locating restaurants or hotels, perform banking functions, obtaining stock market reports and the like. Mobile telephones are somewhat more user friendly as they allow a caller to talk directly to the called person at the instant that the call is made, provided the person being called answers the telephone.
At the present time, the use of wireless terminals such as pagers and mobile telephones is widespread and their use is continuing to grow. Currently, users of pagers and mobile telephones must manually power-up and power-down their wireless terminal. This is normally done to conserve power and/or to stop incoming messages. Frequently, in an attempt to avoid interruptions and/or conserve battery life, a wireless terminal will be turned off during selected hours of the day and/or night. For example, a mobile telephone may be turned off when the user is at work and does not want to be disturbed by an incoming message or when he is at home and has access to a wired telephone. Often, when a subscriber becomes aware that the battery in the wireless terminal is low, in an attempt to conserve battery power, he will take his wireless terminal out of service by selectively turning it off until it is actually needed.
Although a time out of service procedure initiated by the subscriber by turning off the wireless terminal provides a method for dealing with the problem of low battery power, the procedure has drawbacks. One drawback of turning the wireless terminal off is that at least one more call must be made by the caller to the mobile telephone or to the pager to contact the person being called. Another drawback is that when a call is made to a pager that is off, the caller is not aware that the message was not received by the pager and the called person is not aware that someone has tried to reach his pager. Consequently, neither the calling person nor the called person is aware that the message never went through. In each instance, the subscriber will miss a call and not be aware that a call was missed.
On instructions obtained from a wireless terminal subscriber, a wireless terminal service provider sends a power-down control signal to a wireless terminal. Upon receipt of the power-down control signal, the wireless terminal goes into a sleep mode for a discrete interval of time. In this mode all monitoring functions other than time, date and elapsed time are turned off. At the end of the discrete interval of time, the wireless terminal is automatically powered up. Resending the power-down signal will extend the duration of the power-down state of the wireless terminal. In another embodiment, the control signal can consist of two parts. One part can be the power-down control signal and the other part can be the power-down time duration control signal. The power-down time duration signal determines the duration of the sleep mode. The time duration signal sets a clock which times the sleep mode. At the end of the sleep mode period, the monitoring circuits are powered-up and the wireless terminal is awoke. The wireless terminal service provider (WTSP), by knowing the power-down/power-up time cycle of the wireless terminal, can alert a party attempting to contact the wireless terminal during the power-down period that the wireless terminal being called cannot be reached. The WTSP can also offer other service options. For example, the WTSP can provide the time when the called wireless terminal will next be powered-up, can offer to take a message which will be sent when the called wireless terminal is next powered-up, can offer to cancel any further attempt to send the message to the called wireless terminal, etc.